1. Field of Invention
The present invention relates to an electric connection box. More particularly, the present invention is intended to prevent penetrated water from causing a short.
2. Description of Related Art
An electric connection box to be disposed in the engine compartment has a drainage hole for discharging liquid which has penetrated therein. Some examples of liquid entering in the electric connection box are water from heavy rain, moisture and when high-pressure cleaning liquid blows into an engine compartment of a vehicle.
For example, as shown in FIG. 7, bus bars 3A, 3B and drainage holes 2a, 2b are formed on a bottom wall 2 of the case of an electric connection box 1. Frequently, the electric connection box 1 is disposed over a member 4 mounted in an engine compartment.
It is very difficult to bring the lower surface of the bottom wall 2 of the case of the electric connection box 1 into close contact with the upper surface of the member 4 and a gap H is present therebetween. When liquid penetrates into the gap H and collects, the liquid enters the drainage holes 2a, 2b, which may cause a current leak or electrical short to occur between the bus bars 3A and 3B.
To prevent generation of the current leak or short, one could increase the space the bottom wall 2 of the case at the gap H from the upper surface of the member 4. As a result, it is difficult for the liquid that has penetrated into the gap H to collect and does not enter the drainage holes 2a, 2b disposed upward from the upper surface of the member 4. Thus, it is possible to prevent the generation of the current leak or short.
However, if the electric connection box 1 is spaced at a comparatively long distance from the upper surface of the member 4 to make the gap H large, the entire height of the electric connection box is very large.
This problem occurs not only where the electric connection box 1 is mounted on the member 4, but also where an electric connection box having a lower cover mounted thereon is disposed in the engine compartment.
That is, where bus bars are disposed on the bottom wall of the case of the electric connection box and the bottom wall has drainage holes formed thereon. The lower cover is mounted on the case of the electric connection box, and a short or current leakis liable to occur between the bus bars because of liquid that has been penetrated into the lower cover and collected therein, if the gap between the bottom wall of the lower cover and the bottom wall of the case of the electric connection box is small. Again, to avoid this, it is conceivable to space the bottom wall of the lower cover at a comparatively larger interval from the bottom wall of the case of the electric connection box. However, this makes the electric connection box large.
The present invention has been made in view of the above-described problem. Accordingly, it is an object of the present invention to prevent a current leak or electrical short from occurring between bus bars because of liquid that has penetrated into an electric connection box without widening the gap between the bottom wall of the electric connection box and the member over which the electric connection box is mounted and without making the lower cover-provided electric connection box large.
To achieve the object, according to the present invention, there is provided an electric connection box, disposed in an engine compartment of a vehicle, having a plurality of drainage holes formed on a bottom wall of a case thereof and bus bars mounted on the bottom wall of the case.
A droplet-dividing rib is projected from the bottom wall of the case at a position between the drainage holes adjacent to each other. The droplet-dividing rib is in contact with a surface of a member disposed below the bottom wall of the case, and a space is provided between the bottom wall of the case and the member.
Because the droplet-dividing rib is formed between the drainage holes it divides any water or other liquid that has collected between the bottom wall of the case and the member disposed below the bottom wall of the case. In this way, it is possible to prevent the bus bars inside the electric connection box from being electrically conductive to each other through the water and hence prevent generation of a short.
This construction is preferably used when the electric connection box is a fuse box that is mounted on an upper surface of a battery.
The member disposed below the bottom wall of the case is a battery. A bottom wall of a case of the fuse box is mounted on an upper surface of the battery, with a slight gap provided between the upper surface of the battery and the bottom wall of the case of the fuse box. A lower end of the droplet-dividing rib projected from the bottom wall of the case contacts the upper surface of the battery.
Because the droplet-dividing rib divides water that has collected in a slight gap between the bottom wall of the case of the fuse box and the battery disposed below the bottom wall of the case, the bus bars disposed on the bottom wall of the case of the fuse box do not become electrically conductive to each other through the water. Hence, it is possible to prevent the occurrence of a short or current leak.
Since the fuse box 11 is directly installed on the battery, it is unnecessary to provide the space for the fuse box as in the conventional fuse box. Thus, a limited space in a vehicle can be effectively utilized.
This construction is applicable not only to the gap between the fuse box and the battery, but also to the case where a lower cover is mounted on the electric connection box.
More specifically, in mounting a lower cover on a lower portion of the case of the electric connection box, the droplet-dividing rib is projected from the bottom wall of the case and contacts an inner surface of a bottom wall of the lower cover.
With this, the droplet-dividing rib is provided inside the electric connection box and prevents a short from occurring between the bus bars.